Template Editor is missing on the "Developer Tools/Template" page

I don’t know what I did, but the template editor is missing from the Developer Tools/Template page:

I tried resetting to the demo template and restarting HA - neither did anything.

Any idea how to get the editor back?

Thanks!

It turns out to be issue #15496, triggered by updating to the latest Mac (and iPad) OS releases.

Solved by pulling a new Home Assistant docker image.